Cotton CENTRORADIALIS/TERMINAL FLOWER 1/SELF-PRUNING genes functionally diverged to differentially impact plant architecture

Abstract

Genes of the CENTRORADIALIS/TERMINAL FLOWER 1/SELF-PRUNING (CETS) family influence meristem identity by controlling the balance between indeterminate and determinate growth, thereby profoundly impacting plant architecture. Artificial selection during cotton (Gossypium hirsutum) domestication converted photoperiodic trees to the day-neutral shrubs widely cultivated today. To understand the regulation of cotton architecture and exploit these principles to enhance crop productivity, we characterized the CETS gene family from tetraploid cotton. We demonstrate that genes of the TERMINAL FLOWER 1 (TFL1)-like clade show different roles in regulating growth patterns. Cotton has five TFL1-like genes: SELF-PRUNING (GhSP) is a single gene whereas there are two TFL1-like and BROTHER OF FT (BFT)-like genes, and these duplications are specific to the cotton lineage. All genes of the cotton TFL1-like clade delay flowering when ectopically expressed in transgenic Arabidopsis, with the strongest phenotypes failing to produce functional flowers. GhSP, GhTFL1-L2, and GhBFT-L2 rescue the early flowering Attfl1-14 mutant phenotype, and the encoded polypeptides interact with a cotton FD protein. Heterologous promoter::GUS fusions illustrate differences in the regulation of these genes, suggesting that genes of the GhTFL1-like clade may not act redundantly. Characterizations of the GhCETS family provide strategies for nuanced control of plant growth.